Comparative outcomes of active and passive hearing devices by transcutaneous bone conduction

Conclusion Bonebridge (BB) and Sophono (SP) devices improved hearing; with the BB implant showing a better performance at medium and high frequencies. Furthermore, the BB, as an active implant, showed higher functional gain and increased time of use, when compared to the SP, a passive system. Objectives This study aims to compare surgical and audiological outcomes of SP and BB devices in order to assess and further differentiate the indication criteria. Methods Fourteen patients with conductive and mixed hearing loss were evaluated pre- and post-operatively (BB or SP) (period 2013-2014). Age, gender, surgical history, cause and type of hearing loss, implant use per day, levels of bone and air conduction, and functional gain were recorded. Data was analysed by Wilcoxon singed-rank and Wilcoxon rank-sum tests. Results Fourteen patients (BB; n=10 and SP; n=4) with an average age=25.42 years (CI95=12.41-38.43) were evaluated. The gender relation was equal (1:1), with pre-implantation osseous thresholds of 20.42dB (CI95=11.15-29.69), and pre-implantation aerial thresholds of 70.83dB (CI95=62.52-79.14). The SP wearing time was significantly lower than that of the BB (SP=7-10h/day, BB=8-12h/day; p=0.0323). The functional gain did not differ significantly between the two devices (BB=40.00 +/- 13.19dB, SP=34.06 +/- 15.63dB; p=0.3434), but a significant improvement from pre- to post-implantation was observed (p<0.05). BB and SP decreased auditory thresholds at 1 and 2kHz (< 0.01), respectively. The BB even significantly decreased thresholds at 0.5kHz (p=0.0140) and 4kHz (p<0.0001). No relevant surgical complications were found.